Not using credit card but interest charges get higher every month

I have a Standard Bank Credit card which reflects both a cash finance charge as well as a finance charge.

Please see table below for a breakdown of these charges:

OCTOBER NOVEMBER CASH FINANCE CHARGE 421.54 445.49 FINANCE CHARGE 557.02 589.24

I have not used the credit card for purchases during October and November and I note that the interest rate is the same on both statements.

Please advise why there is a significant increase in these charges from October to November. Shouldn’t these charges be decreasing considering that there have been no purchases on the account and that the balance is effectively dropping.

Same thing for the months of Dec, Jan and Feb. I emailed ********** on 15 November 2017 to enquire - Amanda Mnothoza advised that the team is reviewing the matter and will revert. I followed up on 5 December again - To date I have not yet received a response,